Search found 363 matches

by MalcolmB
Sat Mar 28, 2009 2:58 pm
Forum: General
Topic: Mechanical Speed Controller
Replies: 13
Views: 17595

I really like this. Very tempted to have a go at building one. How does it behave if you demand high torque for takeoff? Just thinking that the current density at the tip of the copper 'commutator' would be very high?
by MalcolmB
Sat Mar 28, 2009 2:04 pm
Forum: Electric Motor Bikes
Topic: OK to paint the controller black?
Replies: 4
Views: 14071

Curiously enough, the colour with the highest emissivity in the infrared range is bright pink.
by MalcolmB
Sun Mar 15, 2009 9:39 pm
Forum: All things battery related
Topic: LiIon/LiFePo Cells Pricing
Replies: 15
Views: 14263

Chris Here's a link to a European distributor of lithium ion that may give some idea of prices at the cheaper end of the market – although again no BMS, which seems to be essential. Simon Sounds like a nice project – a lot more challenging than my mini conversion, but I have very limit...
by MalcolmB
Sat Mar 14, 2009 8:18 pm
Forum: All things battery related
Topic: Lifepo4 cells catch fire!
Replies: 82
Views: 125765

Looking around for more information about the composition of lithium phosphate cells and combustion products, I came across this wiki that I'd not read before: http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery Quote: LiFePO4 is an intrinsically safer cathode material than LiCoO2 and mangan...
by MalcolmB
Wed Mar 11, 2009 1:02 pm
Forum: All things battery related
Topic: Lifepo4 cells catch fire!
Replies: 82
Views: 125765

One thing that the Prius fire and the you tube video show is that these cells can generate tremendous heat when something goes wrong and that heat can easily start a fire even if the cells themselves don't catch fire. I think that's one of the most important messages to come out of all this. It's o...
by MalcolmB
Thu Feb 26, 2009 10:33 pm
Forum: All things battery related
Topic: Lifepo4 cells catch fire!
Replies: 82
Views: 125765

That's a real shock Greg, especially as you obviously put a lot of thought and care into your conversions. I'll be very interested to hear what you think went wrong.
by MalcolmB
Wed Feb 25, 2009 7:30 pm
Forum: Hot off the press....
Topic: Jozzbikes in MCN
Replies: 3
Views: 4654

Well done Steve. I've not seen the article yet but I know MCN have done a few stories on electric motorbikes recently and they've always had a positive slant. Hope they did a good job for you.
by MalcolmB
Wed Feb 25, 2009 7:26 pm
Forum: All things battery related
Topic: Metal interactions
Replies: 7
Views: 7509

Hmm, maybe I misunderstood the application. Are these links likely to get wet? John is right if so.
by MalcolmB
Wed Feb 25, 2009 6:39 pm
Forum: All things battery related
Topic: Metal interactions
Replies: 7
Views: 7509

It's a long time since I put my metallurgy books away, but if I remember right the potential problem with joining aluminium to steel is galvanic corrosion. The aluminium, which is the more reactive, corrodes preferentially if the two metals are connected by an electrolyte. In other words as long as ...

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